Waste Anaesthetic Gas Monitoring in Operating Theatres

Waste gases accumulate in the operating theatre from patient exhalation, mask leakage, and delivery system leaks. Sevoflurane is the most commonly used volatile anaesthetic in Australia. Anaesthetists, scrub nurses, and surgeons working in close proximity to the patient's airway face the highest personal exposure. Poorly fitted laryngeal mask airways and paediatric cases (which often use mask induction) generate higher ambient levels.

Patients exhale residual anaesthetic gases during recovery, exposing PACU nurses and staff to sustained low-level concentrations. Multiple patients recovering simultaneously in an open-plan PACU can create cumulative ambient anaesthetic gas levels. Ventilation effectiveness in recovery areas is often lower than in operating theatres.

Active scavenging systems connected to the anaesthetic machine capture waste gases at the adjustable pressure limiting (APL) valve and ventilator exhaust. System effectiveness depends on proper connection, adequate flow rates, and the integrity of tubing and connectors. Air monitoring during routine surgical cases verifies that scavenging is maintaining ambient concentrations below exposure guidelines.

Electrosurgery and laser procedures generate smoke plumes containing benzene, toluene, carbon monoxide, hydrogen cyanide, formaldehyde, and viable cellular debris including viral DNA. Surgical smoke exposure is a recognised occupational health hazard for operating theatre personnel, particularly during prolonged procedures involving extensive electrocautery.

Typical Worker Groups

Common similar exposure groups (SEGs) assessed for this sub-category.

Regulatory Context

Healthcare facilities are workplaces under the WHS Act. The Australian and New Zealand College of Anaesthetists (ANZCA) guidelines recommend that waste anaesthetic gas concentrations be monitored regularly and maintained below exposure limits. Health monitoring is required for workers with significant exposure to listed hazardous chemicals. The Code of Practice for Managing Risks of Hazardous Chemicals in the Workplace applies to anaesthetic gas exposure. Operating theatre ventilation must comply with AS 1668.2 and provide a minimum of 15 air changes per hour.